Data Sources

Publicly available data files were downloaded from the California State BLM GIS webpage (http://www.blm.gov/ca/gis/). These included wilderness areas, wilderness study areas (WSAs), national monuments, Areas of Critical Environmental Concern (ACECs), and land ownership by agency, which was used to identify National Park Service (NPS), U.S. Fish and Wildlife Service (FWS), and Department of Defense (DOD) lands. Flat-tailed Horned Lizard Management Areas data were obtained directly from the El Centro Field Office. Critical habitat data files were obtained from the FWS critical habitat webpage. Wild and Scenic River (WSR) data, which available on the California State BLM GIS website, were not used because all WSRs in the CDCA were designated after the last update of the data file, and are thus not included in the file. We were unable to obtain data files for Desert Wildlife Management Areas (DWMAs). Critical habitat for the desert tortoise was used instead, as DWMA boundaries generally correspond to desert tortoise critical habitat on BLM land in the CDCA. We were also unable to obtain data files for national trails, the Mohave Ground Squirrel Conservation Area, and areas with cultural or historic resources, so they are not included in this analysis. Data were gathered over the course of several months in late 2009 and early 2010. Any updates that occurred to the data after a file was downloaded to represent a new or changed designation or a correction in the data file is not captured in the data we use in our analyses.